SOX2 and esophageal squamous cell carcinoma: Amplifications of 3p26.33 (SOX2-OT), 8q24.21 (MYC), 14q21.1 (FOXA1) and deletion of 3p12.1 (GBE1) were found as the recurrent CNAs in metastasis group only, which indicated that those CNAs might be associated with metastasis in superficial ESCC.